Patent GB-540824-A (GB)
Title: A process for the production of hydrocarbons
IPC: C07C2/62
Filed: 1939-12-08
Abstract: 540,824. Aliphatic hydrocarbons. NAAMLOOZE VENNOOTSCHAP DE BATAAFSCHE PETROLEUM MAATSCHAPPIJ. Dec. 8, 1939, Nos. 31807 and 31808. Convention dates, Dec. 14, 1938, and May 27, 1939. [Class 2 (iii)] Olefines having at least six carbon atoms in the molecule are continuously fed into a circulating dispersion of isoparaffin and 85 to 110 per cent sulphuric acid at such a rate that the molar ratio of isoparaffins to olefines in the dispersion at the point of introduction of the olefines is at least 2:1, a portion of the dispersion is continuously withdrawn at a point where substantially no olefines remain unreacted, the desired hydrocarbon products are removed from the dispersion thus withdrawn and the unreacted isoparaffins are returned to the circulating dispersion. The reaction is conducted at 50-20 to 50‹C. and the olefines are advantageously diluted with isoparaffins before their introduction. In Fig. 1, the isoparaffins and olefines are fed into the system by pipes 1, 2 respectively and they pass by line 3 and valve 4 into a re-cycled dispersion of sulphuric acid and hydrocarbons in line 5. Isoparaffins may be fed into line 3 by means of pipe 25 or pipe 32. The dispersion is pumped into a reaction chamber 10 by pump 6 and is returned to line 5 by pipe 15. Before entering the reaction tank 10 a part of the circulating mixture passes to a cooler 12. Part of the circulating dispersion is led to a separator 17, the acid portion passing to the pump 6 and the hydrocarbons to a still 27. Some of the hydrocarbons may be used to dilute the olefine feed by returning them through pipe 25. From still 27, unreacted isoparaffins pass by pipe 30 to the olefinic feed. When it is desired to remove normal butane and other inert constituents, the vapour from still 27 is passed to a still 31, the inert constituent leaving by pipe 33. In a modified process employing cracked gasoline as the olefine, a mixing tank 2, Fig. 2, is supplied with cracked gasoline through pipe 1 and isopentane and/or isobutane through pipe 3, and the resulting hydrocarbon mixture containing large excess of isoparaffin is introduced through pipe 6 into a circulating stream of sulphuric acid and hydrocarbons substantially free of olefines flowing in pipe 7 to a pump 8 which forces the mixture through a mixing device 10 to a tank 12. The dispersion, after cooling, then passes to a settling tank 15 or is returned to pipe 7. From the settling tank the acid is returned to pipe 7 and the hydrocarbon product passes either to the mixer 2 through pipe 4 or to a scrubber 21 in which it is treated with caustic alkali. The scrubbed products enter a fractionating column 24, the low boiling constituents being returned directly to pipe 4 through pipe 26 if they are free from inert constituents, and, when they contain the latter, first to fractionating column 28 and then to pipe 4. Debutanized gasoline withdrawn from column 24 is finally freed from heavy products in a column 32. In a further example, a re-formed aviation gasoline containing 28 per cent of olefines which has been treated with phosphoric acid is subjected to the above process. The olefines may be natural in origin or be obtained by catalytic dehydrogenation, cracking or other pyrogenic treatment. Benzene sulphonic acid and heavy metal sulphates are stated to assist the reaction. Specifications 515,367, 526,149 and 531,383 are referred to.